The size of the 10 Iranian missiles used on Al Asad Air Base in Iraq during the Jan. 8 airstrike is to blame for the increased number of service members diagnosed with traumatic brain injuries (TBI), a Pentagon official told reporters Monday.

"The magnitude or size of the munition certainly creates a different exposure for the service members who are in the area of the blast" as compared to the small munitions used against U.S. forces in the past, Air Force Brig. Gen. Paul Friedrichs, Joint Staff Surgeon, said at Monday's briefing.

The official count for those diagnosed with mild TBI or concussion-like symptoms from the attack currently sits at 110 service members; one additional case was announced last week. And while most have returned to active duty, 25 have been transported to the U.S. for more treatment, according to a Feb. 21 news release.

Pentagon officials initially reported that there were no injuries stemming from Iran's retaliatory attack for the Jan. 3 U.S. airstrike that killed Iranian Quds Force commander Maj. Gen. Qasem Soleimani.

"In this case, when they went through, they identified that no one had any acute injuries. No one lost a leg, no one lost an eye, no one lost a limb, which was remarkable given the strength of these munitions," Friedrichs said. "The larger the munition, the larger the blast that's created, the more effect there will be on the human body."

The incident received further public criticism when President Donald Trump referred to the troops' TBI injuries as "headaches" and as the number of diagnoses rapidly climbed in the following weeks.

TBI's symptoms, which can range from dizziness, irritability, headaches and nausea to memory and balance problems, usually go away in about 30 days with therapy and rest. Friedrichs said the service members whose conditions hadn't improved in that time frame would be sent home for more treatment.

He touted advancements in the Defense Department's TBI evaluation process, called the Military Acute Concussion Evaluation 2 (MACE 2), which is automatically activated when a service member has been exposed to multiple blasts or comes within 50 meters of a blast, among other situations.

Both those scenarios occurred during the Jan. 8 attack, triggering the mandatory evaluations.

"It was a real validation of the work over the last 15 years to change how we take care of people who develop traumatic brain injury," he said. "From a medical standpoint, the fact that exactly zero people on this base suffered an acute traumatic injury is extraordinary."

Friedrichs said that, while there are six people still undergoing TBI evaluation, he doubts there will be such drastic increases in the number of service members diagnosed with TBI as there were in the weeks following the Al Asad attack, when reports rose from zero troops impacted to the current count of 110.

"If you look at the bell curve, the biggest group was within the first three weeks and it's really tapered off since then," he said.

Pentagon officials said they have been meeting with lawmakers to answer their questions about the injuries. Friedrichs said specifics on whether the bunkers or other safety measures were adequate will be studied by the Defense and Veterans Brain Injury Center (DVBIC) for years to come.

In the meantime, this has proven to be a "big step forward" for the military medical community, he said.

"From a medical standpoint, I think, the most important lesson for anybody that should be drawn from this is we have developed the ability to screen, diagnose and treat people that's far superior to anything that we've had at any point in military medical history," he said. "And we used it, and every single person that we've identified is getting the treatment that they need."